Air filter with composite end cap

ABSTRACT

The air filter element may include an inner metal liner, an outer metal liner, a filter media, an annular end cap, and a composite end cap The annular end cap is formed over the metal liners such that the metal liners are secured and at least a portion of the filter media is sealed. The composite end cap has a foamed urethane portion and a rigid urethane portion. The foamed urethane portion, which has a central aperture and stand-off apertures, is molded about the central aperture and the stand-off apertures such that the metal liners are secured, at least a portion of the filter media is sealed, and urethane flashing occurs proximate one or more of the central aperture and an outer liner periphery. The rigid urethane portion is molded over the foamed urethane portion such that the stand-off apertures are filled, blocked, and/or sealed.

RELATED APPLICATION

This application is a divisional application of pending U.S. patentapplication Ser. No. 11/254,048 filed on Oct. 19, 2005, which isincorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The present invention relates to an apparatus for filtering impuritiesout of a fluid, and more particularly to an apparatus for filteringimpurities out of air flowing through an internal combustion engine.

BACKGROUND OF THE INVENTION

A conventional air filtration system, such as those used inover-the-road trucks and in agricultural, automotive, and off-highwayequipment, is employed to prevent dirt and dust from entering the enginewith the incoming air supply. These conventional air filtration systemsmay include, among other things, a housing, an air flow tube associatedwith the housing, and a removable and replaceable air filter element.Air filter elements may include an inner metal liner, an outer metalliner, a filter media, and a pair of end caps. The filter media isdisposed between the metal liners. The end caps generally secure themetal liners on opposing sides of the filter element and seal all or aportion of the filter media. It is known to use metal and polymeric endcaps as indicated generally by U.S. Pat. No. 6,413,289 entitled “ReverseFlow Air Filter Arrangement” and U.S. Pat. No. 5,484,466 entitled “AirFilter Element With Radial Seal Sealing Element”, the entire disclosuresof which are incorporated by reference. The present invention relates toimprovements in polymeric end caps.

BRIEF SUMMARY OF THE INVENTION

In one aspect, the invention provides an air filter element thatcomprises a tubular ring of pleated filter media, a first annular endcap, and a second composite end cap. The tubular ring of pleated filtermedia extends between first and second ends. The first annular end capis located over the first end such that the first end is sealed. Thesecond composite end cap comprises a foamed polymeric portion and arigid urethane portion.

The foamed polymeric portion has a central aperture and stand-offapertures. The foamed polymeric portion is molded about the centralaperture and the stand-off apertures such that the second end is sealed.Flashing occurs proximate an outer liner periphery. The rigid urethaneportion is molded over the foamed urethane portion and fills thestand-off apertures such that the stand-off apertures are blocked.

In another aspect, the invention provides an air filter element thatcomprises an inner metal liner, an outer metal liner, a filter media, anannular end cap, and a composite end cap. The outer metal liner isconcentrically spaced outside the inner metal liner and defines an outerliner periphery. The filter media is disposed between the inner andouter metal liners. The annular end cap is formed over the inner andouter metal liners such that the inner and outer metal liners aresecured and at least a portion of the filter media is sealed. Thecomposite end cap comprises a foamed urethane portion and a rigidurethane portion.

The foamed urethane portion has a central aperture and stand-offapertures. The foamed urethane portion is molded about the centralaperture and the stand-off apertures such that the inner and outer metalliners are secured, at least a portion of the filter media is sealed, anannular groove is formed on an underside of the composite end cap, theannular groove having a plurality of transverse ribs therein, andurethane flashing occurs proximate one or more of the central apertureand the outer liner periphery. The rigid urethane portion is molded overthe foamed urethane portion such that the stand-off apertures areblocked.

In a further aspect, the invention provides an air filtration systemthat comprises a housing, an air flow tube, and an air filter element.The air flow tube is securable to the housing. The air filter elementcomprises an inner metal liner, an outer metal liner, a filter media, anannular end cap, and a composite end cap. The outer metal liner isconcentrically spaced outside the inner metal liner and defines an outerliner periphery. The filter media is disposed between the inner andouter metal liners. The annular end cap is formed over the inner andouter metal liners such that the inner and outer metal liners aresecured and at least a portion of the filter media is sealed. Thecomposite end cap comprises a foamed urethane portion and a rigidurethane portion.

The foamed urethane portion has a central aperture and stand-offapertures. The foamed urethane portion is molded about the centralaperture and the stand-off apertures such that the inner and outer metalliners are secured, at least a portion of the filter media is sealed,and urethane flashing occurs proximate one or more of the centralaperture and the outer liner periphery. The rigid urethane portion ismolded over the foamed urethane portion such that the stand-offapertures are filled.

Other aspects, objectives and advantages of the invention will becomemore apparent from the following detailed description when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings incorporated in and forming a part of thespecification illustrate several aspects of the present invention and,together with the description, serve to explain the principles of theinvention. In the drawings:

FIG. 1 is a side elevation view of an exemplary embodiment of an airfilter element, including a cut-away portion, constructed in accordancewith the teachings of the present invention;

FIG. 2 is a bottom plan view of the air filter element of FIG. 1;

FIG. 3 is a fragmentary side cross-section view of the air filterelement of FIG. 1 taken along line 3-3;

FIG. 4 is a fragmentary side cross section view of the air filterelement of FIG. 1 highlighting a composite end cap;

FIG. 5 is a fragmentary side cross section view of the air filterelement of FIG. 1 highlighting another embodiment of the composite endcap; and

FIG. 6 is an exploded plan view of an air filtration system employingthe air filter element of FIG. 1.

While the invention will be described in connection with certainpreferred embodiments, there is no intent to limit it to thoseembodiments. On the contrary, the intent is to cover all alternatives,modifications and equivalents as included within the spirit and scope ofthe invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, an air filter element 10 is illustrated. The airfilter element 10 comprises an inner liner 12, an outer liner 14, afilter media 16, an annular end cap 18, and a composite end cap 20. Asshown in the cutaway portion of FIG. 1, the outer liner 14 isconcentrically spaced outside the inner liner 12 and the filter media 16is disposed between the inner and outer liners 12, 14. The filter media16 can be any of the conventional filter media as known in the art suchas, for example, a cylindrical pleated cellulose filter media. Likewise,the inner and outer liners 12, 14, can be metal cylinders that areexpanded, perforated, and the like, as known by those skilled in theart. The outer liner 14 defines an outer liner periphery 22.

The annular end cap 18 includes central aperture 24, as shown in FIG. 1,and is constructed of a flexible, compressible material such as, forexample, a polymeric material, plastisol, non-foaming urethane, foamingurethane, and the like. In certain embodiments, the annular top end cap18 can be a potted, pre-formed metal or plastic end cap carrying agasket if deemed necessary. As such, the annular end cap 18 is able tosecure in place the inner and outer liners 12, 14 as well as seal atleast a portion of the filter media 16. The annular end cap 18 may bevertically disposed above the composite end cap 20 as oriented in FIG.1.

Referring to FIGS. 2-3, the composite end cap 20 comprises a foamedurethane portion 26 and a rigid urethane portion 28. The foamed urethaneportion 26 is formed when a foaming urethane is introduced or flowedinto a mold having a plurality of stand-offs therein. Guided by themold, the foaming urethane flows over and around the inner and outerliners 12, 14, the filter media 16, and the stand-offs and forms acentral aperture 27. When the foaming urethane hardens (i.e., cures),the inner and outer liners 12, 14, are secured within the composite endcap 20 and all or a portion of the filter media 16 proximate the end cap20 is sealed.

As best shown in FIG. 2, when the air filter element 10 is extractedfrom the mold, a plurality of stand-off apertures 30 are left in thefoamed urethane portion 26. A rigid urethane portion 28 is formed overthe foamed urethane portion 26, as shown in FIG. 3, to fill, block,and/or seal these stand-off apertures 30. This rigid urethane portion28, which is generally disposed over and around the foamed urethaneportion 26, is used to cap the stand-off apertures 30. The rigidurethane that is used to construct the rigid urethane portion 28experiences little or no expansion during curing (i.e., hardening)compared to the foaming urethane that is used to form the foamedurethane portion 26.

In one embodiment, as depicted in detail in FIG. 4, the foamed urethaneportion 26 includes a well portion 32. The well portion 32 results inthe formation of a dam 34 that is vertically above the well portion 32(as oriented in FIG. 4) when the foamed urethane portion 26 expands asit cures (i.e., hardens). The dam 34 is employed to provide a boundaryfor the rigid urethane portion 28.

In a further preferred embodiment, as illustrated in FIG. 4, the foamedurethane portion 26 of the composite end cap 20 includes a plurality oftransverse ribs 40. These transverse ribs 40 inhibit and/or prevent aseal from forming between the air filter element 10 and a correspondingannular internal rib within housing 50 (FIG. 6). Because the transverseribs 40 inhibit and/or prevent the formation of a seal between the airfilter element 10 and the housing 50, no negative pressure or vacuum iscreated in the housing and removal of the air filter element 10 from thehousing is quick and easy.

In another embodiment, as illustrated in FIG. 5, a dam 142 is formedwithout the use of a well such as, for example, the well 32 of FIG. 4.However, like before, the dam 142 bounds the rigid urethane portion 128.Therefore, the rigid urethane portion 128 is positioned over the foamedurethane portion 126 and is disposed between the periphery 136 of theinner liner 112 and the dam 142 to seal and/or cap the stand-offapertures 130.

As illustrated in FIG. 5, when the foaming urethane is used to constructthe foamed urethane portion 126, urethane “flashing” 138 occurs.Urethane flashing 138 is the result of the foaming urethane expanding asthe foaming urethane cures (i.e., hardens). Because expansion of thefoaming urethane is unpredictable, the flashing 138 generates an unevenand/or non-symmetrical outer periphery on the composite end cap 120.

Still referring to FIG. 5, in an exemplary embodiment, the foamedurethane portion 126 includes an annular groove 144 sized anddimensioned to engage with a corresponding portion on a housing 50 (FIG.6). Again, in order to prevent a seal from forming between the airfilter element 10 and the housing 50, a plurality of transverse ribs 146are disposed within the annular groove 144.

In FIG. 6, an example of an air filtration system 48 is illustrated. Asshown, the air filtration system 48 includes a housing 50, an air flowtube 52, a cover 54, and the air filter element 10. When the airfiltration system 48 is assembled, the air filter element 10 is placedin the housing 50 and, thereafter, the cover 54 is secured to thehousing. The transverse ribs 40, 146 (FIGS. 4 and 5) on the air filterelement 10 inhibit and/or prevent a seal from forming between the airfilter element and the housing 60.

When the filter is installed in the housing 50 and the cover 54 istightened, axial and/or radial seals are formed by both the end caps 18,20 to prevent short circuitry of air past the filter media 16. With theair filter element 10 in the housing 50, air flows in the cover 54 andpasses through the air filter element 10 such that debris, contaminants,impurities, and the like are removed from the air supply. The air thenflows through the air flow tube 52. Therefore, clean air can be providedto, for example, an internal combustion engine.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) is to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. Recitation of ranges of valuesherein are merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein. All methodsdescribed herein can be performed in any suitable order unless otherwiseindicated herein or otherwise clearly contradicted by context. The useof any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventor(s) for carrying out the invention.Variations of those preferred embodiments may become apparent to thoseof ordinary skill in the art upon reading the foregoing description. Theinventor(s) expect skilled artisans to employ such variations asappropriate, and the inventor(s) intend for the invention to bepracticed otherwise than as specifically described herein. Accordingly,this invention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

1. A method for making a filter element comprising the steps of: providing a tubular ring of filter media extending between first and second ends; providing a first annular end cap located over the first end; and providing a second composite end cap comprising a foamed polymeric portion having a central aperture, the foamed polymeric portion being molded such that the second end is sealed; and a rigid portion molded over the foamed polymeric portion.
 2. The method of claim 1, wherein the foamed polymeric portion having apertures.
 3. The method of claim 2, wherein the apertures are stand-off apertures.
 4. The method of claim 2, wherein the foamed polymeric portion includes a well portion disposed between the central aperture and the stand-off apertures.
 5. The method of claim 4, wherein the well portion expands upwardly toward the annular end cap to form a dam portion.
 6. The method of claim 5, wherein the dam portion provides a boundary for the rigid urethane portion disposed between an inside surface of the filter media and the central aperture.
 7. The method of claim 3, wherein at least one of the stand-off apertures are filled and sealed by the rigid portion.
 8. The method of claim 1, wherein the foamed polymeric portion has a constant diameter portion.
 9. The method of claim 1, wherein the foamed polymeric portion expands into pleats formed in the filter media.
 10. The method of claim 1, wherein the foamed polymeric portion expands into the filter media.
 11. The method of claim 1, wherein a plurality of ribs are disposed in the central aperture to inhibit and prevent a seal from forming between the filter element and a housing.
 12. The method of claim 1, wherein the foamed polymeric portion forms flashing proximate an outer surface of the filter media.
 13. The method of claim 1, further providing an outer liner.
 14. The method of claim 1, further providing an inner liner.
 15. The method of claim 1, wherein the first end is sealed. 